Dimmable incandescent bulbs, which operate on AC circuits, are well known. Typically they require a separate dimmer switch, also known as a legacy dimmer, which is wired to the electrical connection. Legacy dimmers employ a triode AC switch, also known as a TRIAC.
Some dimmable incandescent bulbs do not require a separate dimmer switch. For example, U.S. Pat. No. 5,214,354 discloses an incandescent bulb comprising an electronic control module which is coupled to the screw fitting and the circuit. The module comprises a TRIAC.
Dimmable LED bulbs, which operate on DC circuits, are also well known. Most also require a separate dimmer switch which is wired to the electrical connection. Certain dimmable LED bulbs are compatible with legacy dimmers while others require a dimmer switch for use specifically with an LED bulb. Still other dimmer switches, known as universal dimmers, can control the dimness settings for both incandescent and LED lights as well as CFL and halogen lights. These dimmer switches have a more complicated electronic configuration and typically comprise a semiconductor switch, such as a MOSFET, and integrated circuit (IC).
More recently, some dimmable LED bulbs do not require a traditional dimmer switch to control the light's brightness. For example the dimmable LED bulbs known as Philips Hue (TM) and LIFX (TM) are designed for the brightness to be controlled using a WiFi controlled application, such as a mobile phone application or other computer control mechanism, which provides dimmer control of the bulb. This requires the use of a smart phone or access to a computer and communication network for the user to transmit communications, including the desired light intensity level, to the dimmable light bulb in order to dim the bulb.
Some LED bulbs incorporate a chip such as the NCL30083 IC made by Semiconductor Components Industries, LLC (Phoenix, Ariz.). This a PWM current mode controller which provides 5 step dimming functionality for an LED circuit, controllable by toggling an on/off switch. The set light intensity levels are 70%, 40%, 25%, 10% and 5% of output current. The 5% output current corresponds to 17% of perceived brightness. The chip, which is not a microcontroller, does not allow for continuous dimming up and down or a simple way for the user to quickly and intuitively set the desired light intensity level.
Dimmers and complicated methods for dimming LED bulbs do not address the need in the market to replace standard incandescent bulbs with dimmable LED bulbs, which can be dimmed to desired levels in any light fixture, with or without a dimmer switch or other complicated communication protocols.
There is a need for a simple way to control a continuous dimming function in a LED light to a desired light intensity which does not rely on a dimmer switch. There is also a need for a dimmable LED light which can dim to a plurality of desired light intensity levels with or without a separate, external dimmer switch.